Bladder Function after SCI Flashcards
How serious is bladder dysfunction after SCI?
Possible consequences:
-early 1900s SCI was a fatal condition
-i.e. 80% of WWI soldiers with SCI died within a few weeks, most commonly as a result of urosepsis
-during WWII urinary catheters were introduced and mortality secondary to urinary disease decreased (37% of WWII soldiers with SCI died of renal failure)
-invention of urinary catheters in ww1 changed the face of spinal cord injury the most (besides the wheel chair)
-today individuals with complete tetra are still 40x more likely to die from diseases of the urinary system than the able bodied
-lack of bladder control can cause bacteria to flourish and without treatment can cause death in a few weeks
Aside from death due to urosepsis, bladder dysfuction after SCI may result in?
-urinary incontinence (not getting rid of)
-inability to urinate: UTI, autonomic dysreflexia, renal failure
-penile erosion- lack of oxygen and blood because of catheter
-urine will trickle down ureters and go into bladder
-pee has to go below external sphincter or pelvic floor muscles to exit
Innervation of the urinary system?
-detrusor muscle: receives parasympathetic (s2-s4) and sympathetic (T11-L1) innervation
Parasympathetic–> exciting contraction
Sympathetic–> inhibiting contraction, relaxing bladder (not always exciting but preparing fight or flight)
external sphincter and pelvic floor muscles: receive somatic innervation (S2-S4), most spinal cord injuries above bowel location therefore majority will result in urinary issues
Peeing…
also known as urination, micturation
1.with little or no urine in the bladder, sympathetic outflow to the detrusor muscle dominates
2.when critical volume of urine accumulates (trickles down) in the bladder (400-450ml)
3.input to detrusor muscle changes from sympathetic to parasympathetic
4.increased muscular tone in bladder, and activation of stretch receptors (in bladder wall)
5.micturation reflex
Peeing depends on if you had that reflex and if you can control, inhibit, and cause reflex
Spinal cord will send reflex back to intrusive muscle
Micturation reflex?
1.critical volume
2.parasympathetic outflow to detrusor
3.increased bladder pressure and activation of stretch receptors
4.bladder neck is forced open and activation of stretch receptors
5.increased parasympathetic outflow and detrusor muscle AND reflex relaxation of external sphincter
Feedforward cycle in which more parasympathetic outflow, and will continue until bladder neck is forced open
Continence?
- continence is maintained in part by the structure of the urethra and bladder
- continence is maintained by the external sphincter and pelvic floor muscles which are under reflex and voluntary control
A) reflex control of pelvic floor muscles: (allows continence without constant conscious thought)
-bladder filling causes contraction of pelvic floor muscles (which compresses urethra)
-holding in pee
-pinching off urethra which holds back pressure to pee and maintains continence
-by reflex contracting, bladder filling sends messages to spinal cord
B) voluntary control of external sphincter and pelvic floor muscles
-when really having to go pee, and sends motor information down to s2-s4 (sending outflow to detrouser in response)
Sensation from full bladder..
1.sensation from full bladder (stretch receptors)
2.sacral cord (s2-s4)
3.sensory info ascends to cortex (via dorsal columns and L.S.T)
4.motor info descends to s2-s4 (via cortico- and reticulospinal tracts)
5.inhibition of parasympathetic outflow and detrusor and excitation of external sphincter and pelvic floor muscles
Voluntary peeing:
- sensation from full bladder (stretch receptors)
- sacral cord (s2-s4)
- sensory info ascends to cortex (via dorsal columns and LST)
- motor info descends to S2-S4 (via cortico- and reticulospinal tracts)
- increases parasympathetic outflow to detrusor
AND relaxation of external sphincter and pelvic floor muscles AND drop of pelvic floor muscles, contraction of abs
Complications in bladder function following SCI?
-bladder function following (complete) sci depends largely on the integrity of the micturation reflex
possible outcomes:
-areflexive bladder: cannot empty bladder on reflex
-reflexive bladder: can pee on reflex which leads to detrusor sphincter dyssynergia
*during spinal shock there are no reflexes. Therefore, the bladder is generally flaccid (areflexive) for 3-6 weeks after SCI
What is areflexive bladder?
- occurs when the sacral micturation reflex is disrupted
-i.e. damage to S2-S4 or cauda equina injury
peeing is hindered:
1. no parasympathetic outflow to detrusor muscle in response to stretch
2.functional sphincter is still intact as bladder fills
*overflow or dribbling incontinence may occur when bladder pressure increases to very high levels, but large volume of urine remains in bladder (UTI, sepsis, stones, AD)
What is reflexive bladder?
-occurs in those with intact s2-s4 segments (micturation reflex), but disrupted descending input to s2-s4
-voluntary peeing ability is lost
-bladder will empty reflexively (not completely) once there is a sufficient stretch on the bladder wall (UTI, sepsis, stones, AD)
- catheterization is required to prevent bladder accidents, although peeing may be elicited at planned intervals via stroking, pressing or hitting the abdomen, stroking the inner thigh or pulling public hair
Vast majority of people will have this
If brain not involved- will empty
If Women never learn how to retrain, have to wear a diaper for the rest of life
Most women become so familiar with there peeing habits
Knows when she should go to bathroom
Keeps track of water going into body
May have to physically push bladder
what is Detrusor sphincter dyssynergia?
-occurs in some individuals with reflexively functioning bladders
-a condition in which the external sphincter contracts simultaneously with or immediately following the contraction of the detrusor muscle
Detrousor and sphincter should act in synergy, but can be dysnergiatic
Detrouser contracts, sphincter contracts —> synergy
Detrouser relax, sphincter contracts—> not synergy
Can result in bladder being stagnate, and can go back up
Complications following detrusor sphincter dyssynergia?
-stagnant urine in bladder: UTI, Sepsis, stones
-increased pressure in bladder:
-AD (autonomic dysreflexia), vesicoureteral reflex: backflow of urine into the ureters
hydronephorosis: kidneys distended with urine, may lead to kidney damage and failure (with severe pain)
Pyelonephritis: inflammation of the kidneys, usually due to bacterial infection, may lead to kidney damage and failure
bladder management following SCI? The ultimate goal of bladder management techniques after SCI are to ensure?
-complete emptying of the bladder at appropriate times
but there are many health complications that may result from various bladder management techniques
ex: catheterization- UTI, physical trauma, bladder cancer- dragging catheter up urethra can cause high risk of UTI and physical trauma
Early bladder management following SCI:
-during spinal shock there are NO reflexes, and therefore peeing must be aided by catheterization
indwelling catheter: (leaving catheter in all day, constantly raining urine), less work for nursing staff, increased risk of urethral damage, UTI
intermittent catheterization:
-every 4-6 hours (reduces risk of UTI)
-mild pressure increases in bladder may facilitate returned bladder muscle tone.
-will get some atrophy
-don’t want a lot of residual volume (want to get rid of as much as possible)
